If you have a bunch of expensive stuff collecting dust in your closet or garage, it might be time to sit down with Spendster and repent for your consumer gluttony. A project from the National Endowment for Financial Education, Spendster asks folks to calculate how much they've spent on stuff they simply don't need, and to share their stories. The videos already on the site are a lesson in humility that just might change your habits. And you can use the Spendster calculator to reveal the real cost of those impulse buys, expressed in credit card interest fees, how much you'd have if you bought into Google's IPO or just deposited into an interest-bearing savings account.